The present invention relates generally to fire-barriers and more particularly to one-step, drop-in installation, intersection-space fire-barriers sized and shaped for installation into accepting intersection-spaces formed by the spaced intersection of at least two expansion-joint spaces that each occur between different sets of adjacent spaced structural building units, each of said expansion-joint spaces defined by a plane, said plane defined by a set of three non-collinear points with each point defined by a set of x, y, z coordinates from the same coordinate system with no two of said coordinate sets being identical.
The background information discussed below is presented to better illustrate the novelty and usefulness of the present invention. This background information is not admitted prior art. The particular versions of the invention as described below are provided, in part, as illustrative and exemplary. Thus, the described versions should not be taken as limiting. Additionally, the invention is not limited to the examples provided.
Customarily, buildings were built with static joints. Modern building codes, however, require that building design and construction take into account factors that can, over time, change the physical dimensions of a structure. These factors include extreme or repetitive changes in temperature, the force of wind impinging on the building, forces due to seismic events, settling of the subsoil, remodeling of the building, or excavation on or near the site, among other factors. To accommodate the stress on a structure caused by these factors without compromising the integrity of the building, architects and builders design the structure in sub-units where each sub-unit is spaced a small distances away from each of its neighboring sub-units creating spaces referred to as either “expansion-joint spaces,” expansion-joints,” or, “joint-spaces.” Structural sub-units include wall, floor, and ceiling units.
Expansion-joints provide for differential building and building unit movement to take place without risking damage to the whole structure. These joints can widen or narrow to accommodate differential movement of the adjacent spaced structural units and/or can reduce the stress caused by shear motion of the adjacent structural units. Dynamic moveable joints are also often referred to in the trade as “construction joints,” “soft joints,” “dynamic voids”, and “seismic joints.” Expansion-joints or voids often occur, for example, where two wall sections, a wall and a floor, or a wall and ceiling meet, for example.
While the presence of expansion-joints improves the integrity of the structure as a whole, they present a major risk to the structure in the event of a fire. The joint-spaces provide pathways for flame, heat, and smoke to spread rapidly throughout the structure by utilizing what is known as the “chimney effect,” which provides for an updraft of heated air rising through the structural gaps. Building codes for commercial structures generally require the installation of tested fire-barriers capable of preventing flame and smoke from passing through expansion-joints into adjoining areas.
Some of the earliest fire-barriers available include fire retardant and/or intumescent putties, caulks, wraps, and mats. These fire-barrier products however, although suitable for static joints, are generally not suitable for acting as fire-barriers for dynamic joints. To reduce the risk created by the chimney effect due to the spaces associated with dynamic expansion-joints, a number of attempts have been made to block the joints with fire resistant materials. A dynamic expansion-joint fire-barrier needs to be capable of accommodating the complex differential movement of the building structural units and to retain its resiliency over an extended period of time under dynamic conditions. Further, during a fire event, the joint is likely to be subject to even greater stress, thereby making it essential that the fire-barrier retains its integrity to prevent the migration of heat, flame, and smoke.
Some of the earliest commonly available fire-barriers were generally made of fire resistant materials, such as fire brick, which typically may be either rigid and/or brittle, or fire-barrier blankets constructed of refractory fibers that are flexible but can be easily damaged.
In order for the rigid and brittle materials to be used to seal building joints while maintaining a degree of flexibility requires first creating hollowed out regions within the structural units that meet at a joint that is to be sealed with a fire-barrier. The fire-barrier, which consists of a thin layer of material of appropriate high-temperature properties, is then inserted into both hollowed gaps at the ends of the adjacent structural units. Thus, the widening or narrowing or shear motion of the adjacent plates is accommodated by the fire-barrier moving in a sliding fashion within the adjacent structural units. As long as the lateral dimensions of the barrier exceed the widest distance between the adjacent structural units during differential movement, the integrity of the barrier should remain. Similarly, when the structural units move towards each other, the barrier should remain undamaged providing that the lateral dimension of the barrier is less than the distance between the bottoms of the hollowed out regions of the structural units. The major drawback of this approach is that the fire resistant material must be thin enough to fit within the hollowed-out areas of the adjacent structural units. Moreover, fabricating the hollowed-out areas further complicates the construction of the building and increases the cost of the construction. Moreover, correct installation of such a barrier in a pre-existing building is difficult and expensive.
On the other hand, fire resistant materials fabricated into thin, flexible fibers can be incorporated into flexible, fire resistant structures resembling a blanket. The advantages of such a material are that the fabrication is not very expensive, the draping of the blanket across a joint is readily accomplished, and any differential movement of the adjacent structural units can be accommodated by incorporating an appropriate amount of slack in the blanket during installation. The blanket, however, is mechanically weak and can be easily damaged by tearing or ripping either accidentally or intentionally during or after installation thus largely compromising the integrity of the fire-barrier. A number of attempts have been made to protect the blanket from such mechanical damage. These have generally relied on the fabrication of a composite blanket which incorporates the fire resistant material between layers of a stronger, protective material such as metal foils or metal screens. The fire resistant layer can freely move with respect to these protective layers or they may be attached together via threads or similar attaching means.
Given the wide variety of movements that may occur between structural elements in a building, particularly one situated in a seismically active region, there still remains the possibility of gaps appearing in the fire-barrier. To reseal these gaps in the event of a fire, intumescent materials are frequently added to the barrier. These are materials that expand when rapidly heated and at the same time have fire resistant properties. Thus, these provide a second method of sealing the structural gap in a building.